Emergency alarm systems, in which messages are transmitted by radio, offer the user many advantages. The emergency alarm systems thereby comprise monitoring sensors as peripheral elements, which if an emergency situation, e.g. fire or an intruder, is detected, transmit an emergency alarm message via a radio link to a center or master station (to be understood as repeaters), where further measures such as an alarm message to the fire service or police are initiated to eliminate the emergency.
A method for radio transmission in an emergency alarm unit is known from EP 833288, in which measured data can be transmitted from a monitoring sensor to the central unit via further monitoring sensors acting as intermediate stations, if a direct radio link to the center does not exist or fails due to inadequate range. A permanent hierarchical link structure is provided for the monitoring sensors for this purpose.
A method for radio transmission in an emergency alarm system is known from EP 1282094, which operates by means of repeaters but is still economical in respect of power, so that battery operation is possible. The receive arrangements are thereby activated cyclically at predefined times and users that are ready to transmit send a preamble, which results in the users provided for receive purposes remaining activated until the end of the entire preamble once they start to receive and being deactivated again, if no preamble is received. A time is transmitted in the preamble, at which the receiver re-activates to receive the actual data telegram.
The commissioning of such radio-based emergency alarm systems differs from the commissioning of wire-based units. In the case of radio-based emergency alarm systems, the wire present in principle in electrically linked units is not present to act as the first addressing element. In the case of small radio systems, as generally used in private alarm technology, assembly and commissioning are generally carried out by the same person. In the case of large systems, in other words in industrial units, it is desirable to separate these two actions for cost reasons. This is because it has proven economical for an operator, who does not require a profound knowledge of the often complicated electronic system, to fit the equipment first without commissioning the system. The actual commissioning is carried out in a second stage by a trained technician. To this end the central element (gateway or master station) is first switched to so-called register mode. The individual alarm monitors are then registered successively with the gateway. Once all the alarm monitors in a cell have been registered in this fashion, register mode is terminated. This can take place manually or automatically after a specified time or when the cell is full. The problem here is that the person carrying out the registration operation has to handle every monitor. This takes a long time in the case of large units specifically. The commissioning operator may also have to climb ladders to set the individual alarm monitors or to activate the energy supply to the alarm monitors.